Source note · SIP transactions dialogs and call setup
RFC 7647 makes a Globally Routable User Agent URI mandatory for a notifier: a user agent accepting a REFER that creates a subscription must populate its Contact header field with one, and a user agent that might become a notifier needs to include one in the Contact of dialog-forming and target-refresh methods such as INVITE.
Checked 2026-09-16
- Vendor
- IETF
- Product
- Session Initiation Protocol
- Subsystem
- REFER
- Deployment
- not restricted
- Region
- not restricted
- Release range
- Updates RFC 3515
- Checked
- 2026-09-16
Sources
- RFC 7647 — Clarifications for the Use of REFER with RFC 6665 — IETF / RFC Editor · tier 1 standards and regulators · RFC 7647 section 3 Use of GRUU Is Mandatory
Cite this note
APA
WarmTransfer. (2026, September 16). SIP transactions dialogs and call setup: source note xfersem-gruu-is-mandatory-for-a-refer-notifier. WarmTransfer. https://warmtransfer.net/knowledge/claims/xfersem-gruu-is-mandatory-for-a-refer-notifier
BibTeX
@misc{warmtransfer-claim-xfersem-gruu-is-mandatory-for-a-refer-notifier,
title = {SIP transactions dialogs and call setup: source note xfersem-gruu-is-mandatory-for-a-refer-notifier},
author = {{WarmTransfer}},
year = {2026},
url = {https://warmtransfer.net/knowledge/claims/xfersem-gruu-is-mandatory-for-a-refer-notifier},
note = {Source note xfersem-gruu-is-mandatory-for-a-refer-notifier, checked 2026-09-16}
}